[MRCA] PRC-64/DELCO 5300 50th Anniversary Operating Event Saga Therapy Needed

Thu Aug 15 13:20:26 EDT 2013

Really amazing. A QSO between two of 'em! All the work involved. Commendations Gentlemen!

73 Eugene W2HX

-----Original Message-----
From: mrca-bounces at mailman.qth.net [mailto:mrca-bounces at mailman.qth.net] On Behalf Of B. Smith
Sent: Wednesday, August 14, 2013 1:27 PM
To: mrca at mailman.qth.net
Subject: [MRCA] PRC-64/DELCO 5300 50th Anniversary Operating Event Saga Therapy Needed

I had put off getting my DELCO 5300 crystaled up for the "PRC64 50th Anniversary Operating Event" due to various excuses mostly crystals and was going to put the whole Event project in the "Too Hard To Do Box".

Then  Monday**afternoon I received Al's post to thislist(MRCA) with photos illustrating the details of his Delco 5300 "Emergency Crystal
Installation" for 7.030 Kcs.    Drat     Drat --- Al's gonna be on for
the Monday night event and here I am in the abort stage with hours to go before the event started.  Now Al will get all the glory and I will miss
everything    - - - -

I again looked at my crystal inventory and the only transmit  crystal I had was for 7026 in a HC-6 crystal holder and another for 7040 in a HC-50and it was all ready installed in my $55 hamfest without a case DELCO 5300.  But Al broke the crystal barrier , he cheated and sneaked crystals out of the CS-137 /SCR-509 crystal kit and then to top it off he ground one transmit crystal, and thus had a receive and a transmit crystal for 7.030and installed them in his DELCO,  I had not even thought to look inside that crystal kit - - - then I looked in my CS-137 kit and the crystals were there, so I will copy Al's and get on for the event. /Improvise, Adapt/and /Overcome or just copy what some one else has done. /His use of RS-232 connector pins for the HC-50 crystal socket and smashing up a 8 pin octal to get female connectors for the FT-243 holder was ingenious.

TM 11-5820-552-15 manual calls for a CR-78U for the receiver and a CR-89U for the transmitter, my crystal data says that those crystal are designed for a 30 pf load, the FT-243 series in the CS-137 kit are usually designed for a 32 pf load, anyway close enough.

All right now I had the transmit crystal channel 312 pulled from the
CS-137 crystal kit  in my hand and stared at the frequency stamped on the front 7.025 - - - -  good grief 5 kcs, that would take about 4 hours using the traditional tooth paste, pane of glass, and figure 8's method.
Running a temporary test of the rock on the Delco 5300 the frequency actually came out very close to 7.024, that meant 6 kcs of grinding. I was running out of time and could not even use Pete's "secret" chemical method, not enough time to get set up. Anyway

Al used 600 grit sand paper, horror of horrors .   .    . oh well let
her rip. I got out the sand paper, put it on a very flat surface, got the crystal apart, wore latex gloves. I poured a little water on the sand paper and did a couple of  figure 8 patterns  and then tested the crystal in the set, the frequency went up 2 kcs but now the crystal drive was low, ugggggghhh. In my entire electronics career I have never ground a crystal with sand paper --All right grind some more and work our way up to 7.030.
After 3 grinding sessions I was on 7.0295  with the crystal in the set, but still had a low drive level. I took the crystal blank out and
cleaned it with alcohol, inserted it back in the FT-243 holder   and
tried it again and it worked, 3 watts out. I quit while I was ahead.

Then I  tried the receive crystal Ch 306, 6.575 plus the IF of 455 Kcswouldbe 7.030. This would be low injection instead of high but the IF was 455 Kcs so the spread should be OK,  Another Al Klase
improvisation,   so thinking low instead of high I tested the crystal,
nothing, zero, zilch, took it apart. cleaned etc, nothing, I was dead in the water. No receiver.  Then- - - Improvise, Adapt and Overcome. I use my trusty and ole faithful DDS VFO to feed the receiver. Running some quick leads, everything checked.

Monday night at approx 2030 hoursI started listening on 7.030 , thought I heard one PRC-64 call but nothing.At 21:00 hours I started sending "CQ PRC" nothing, no one, no one calling CQ, then several minutes later very faintly I heard my call and heard a number 3 and then aR and a Q, hmmmm.
I turned up the gain and held my speaker closer to my ear and made out Al's call. I acknowledge and sent him a series of R's just to make sure he would confirm my transmission.Later on I worked him again and perhaps another time later on, his computer generated CW was perfect.Did I work any other stations? NO But I considered the mission a success and since I worked Al twice and maybe a partial I decided to count my total score at 2 1/2 contacts.Mission Accomplished.

It great to take a piece of military gear and actually put it on the air instead of just letting it set on the shelf.

A short Video of my Delco 5300 VFO operation can be found at:

http://k4che.com/Delco%20DDS/del.wmv

Some ideas for a battery box can be found at:

http://home.comcast.net/~smithab11/DELCO%20ver%202.htm

Now I have to go mow grass.

73

Z

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